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14/01/2005, 08h26
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Maximum Tech: Suspension Tuning 101
2005 Yamaha Mono-Shock RA - 121-inches of 11.5-inches of Butt Cushion
1/13/2005
TOP STORY
Steve Franta
Yamaha has good suspensions. They are simple in design, easy to adjust and really work quite well. They are just different. A “conventional” suspension with the twin torsion springs in the back and single coil-over-shock spring in the front has somehow eluded Yamaha for the past decade or so…until 2005. But rather than settle for the same-‘ol, same-‘ol, Yamaha not only introduced their version of the “conventional” rear suspension, but also four other new ones to go with it. This article series of Suspension Tuning 101 will go into tuning detail on each of Yamaha’s suspensions and will follow up with tuning other rear suspensions along with front suspension tuning. But to start this off right, we must start with probably the most innovative suspension to come along since the original M-10 – the Yamaha Mono-Shock RA.
Last spring, Yamaha introduced their 2005 Mono-Shock RA Rear Suspension on the RX-1 and RX-1ER models. This high-performance rear suspension features a Kayaba aluminum body 46mm high-pressure gas shock and a remote twenty-three position adjustable shock damping system. Included with the mono-shock is a cam-type spring preload adjuster and a single adjustable control rod weight transfer system and single adjustable limiter strap. We will cover each of these tuning components in detail, so read on my friend.
The easiest and first component that should be adjusted is the Mono-Shock Cam Preload Adjuster which is used to set the appropriate ride height for the rider weight. This cam can be turned to seven different preload settings ranging from a rider weight of 100 lbs. to 300 lbs. If further adjustment is needed, the cam can be repositioned 10mms or 20mm up from the standard position. This gives the Mono-Shock RA quite a range of adjustment. This cam is adjusted by using the spanner wrench found in the RX-1’s tool kit and it can be easily rotated by setting the sled on its side and rotating the cam. If you need to reposition the cam, you will have to remove the shock from the suspension. Once removed and using a special tool, compress the shock spring and slide the cam out of position. Move the cam retainer c-clip to one of the other grooves. Replace the cam and release the spring and install the shock back into the sled. There are a total of twenty-one possible preload settings for the ultimate in fine-tuning.
The other adjustment that can be performed on the Mono-Shock RA is the twenty-three position Adjustable Shock Damping used to adjust shock and ride comfort. This component primarily adjusts rebound damping and also has a lesser effect on compression damping. The standard setting is in the middle position so it can be turned 11 clicks softer (clockwise) or 11 clicks harder (counterclockwise). This dial is connected to the shock via a speedometer drive-type cable. For fine tuning and ride comfort, use damping adjuster after setting the preload.
The Adjustable Control Rod System is used to adjust weight transfer and acts as a floating link between the front and rear suspension arms. Under acceleration, the front of the sled raises while the rear suspension arm compresses, transferring weight from the front to the rear. The control rod is connected to the rear arm, and extends while the rear arm compresses. When the control rod reaches its maximum length it couples the front and rear arms stopping the weight transfer action. The control rod’s maximum length can be adjusted which adjusts when the suspension is coupled. By increasing the maximum length it will increase the weight transfer. Reducing the maximum length reduces the weight transfer. The adjuster is threaded and can be turned in or out to allow more or less rod movement and weight transfer. The total range of the adjuster is 20mm with the standard position set in the middle. This means that there is 10mm on either side for more or less transfer depending on what an individual likes. An adjuster wrench is provided in the tool kit with measuring marks and indicators for standard, minimum and maximum settings. Before adjusting the control rod, clean the threads and use a spray lube before moving the locknut and adjuster.
The last component that can be adjusted is the front limiter strap. This strap is located on the front rail and affects the amount of front rail upward travel. The limiter strap has five mounting holes. The standard position is the second hole from the top. That means one longer position is available to put less weight on the skis, offering more weight transfer. The three shorter settings would increase the weight on the skis and offer less weight transfer. The limiter strap determines the position of the front rail and front arm travel. It also affects ride comfort, handling and weight transfer. This is a very sensitive adjustment, so we recommend the limiter strap be left in the stock position for most conditions; however, it is useful for racing or straight running applications and deep snow applications.
Yamaha does offer additional front and rear suspension springs for even more range. Ask your Yamaha dealer which spring would best suit your rider weight and needs.
This concludes this lesson in Suspension Tuning 101 on the all-new Yamaha Mon-Shock RA suspension. Our next lesson will be on the new Yamaha ProComfort Suspension, so check back only on Maximum Sled for Suspension Tuning 101.
Maximum Tech: Suspension Tuning 101
2005 Yamaha Mono-Shock RA - 121-inches of 11.5-inches of Butt Cushion
1/13/2005
TOP STORY
Steve Franta
Yamaha has good suspensions. They are simple in design, easy to adjust and really work quite well. They are just different. A “conventional” suspension with the twin torsion springs in the back and single coil-over-shock spring in the front has somehow eluded Yamaha for the past decade or so…until 2005. But rather than settle for the same-‘ol, same-‘ol, Yamaha not only introduced their version of the “conventional” rear suspension, but also four other new ones to go with it. This article series of Suspension Tuning 101 will go into tuning detail on each of Yamaha’s suspensions and will follow up with tuning other rear suspensions along with front suspension tuning. But to start this off right, we must start with probably the most innovative suspension to come along since the original M-10 – the Yamaha Mono-Shock RA.
Last spring, Yamaha introduced their 2005 Mono-Shock RA Rear Suspension on the RX-1 and RX-1ER models. This high-performance rear suspension features a Kayaba aluminum body 46mm high-pressure gas shock and a remote twenty-three position adjustable shock damping system. Included with the mono-shock is a cam-type spring preload adjuster and a single adjustable control rod weight transfer system and single adjustable limiter strap. We will cover each of these tuning components in detail, so read on my friend.
The easiest and first component that should be adjusted is the Mono-Shock Cam Preload Adjuster which is used to set the appropriate ride height for the rider weight. This cam can be turned to seven different preload settings ranging from a rider weight of 100 lbs. to 300 lbs. If further adjustment is needed, the cam can be repositioned 10mms or 20mm up from the standard position. This gives the Mono-Shock RA quite a range of adjustment. This cam is adjusted by using the spanner wrench found in the RX-1’s tool kit and it can be easily rotated by setting the sled on its side and rotating the cam. If you need to reposition the cam, you will have to remove the shock from the suspension. Once removed and using a special tool, compress the shock spring and slide the cam out of position. Move the cam retainer c-clip to one of the other grooves. Replace the cam and release the spring and install the shock back into the sled. There are a total of twenty-one possible preload settings for the ultimate in fine-tuning.
The other adjustment that can be performed on the Mono-Shock RA is the twenty-three position Adjustable Shock Damping used to adjust shock and ride comfort. This component primarily adjusts rebound damping and also has a lesser effect on compression damping. The standard setting is in the middle position so it can be turned 11 clicks softer (clockwise) or 11 clicks harder (counterclockwise). This dial is connected to the shock via a speedometer drive-type cable. For fine tuning and ride comfort, use damping adjuster after setting the preload.
The Adjustable Control Rod System is used to adjust weight transfer and acts as a floating link between the front and rear suspension arms. Under acceleration, the front of the sled raises while the rear suspension arm compresses, transferring weight from the front to the rear. The control rod is connected to the rear arm, and extends while the rear arm compresses. When the control rod reaches its maximum length it couples the front and rear arms stopping the weight transfer action. The control rod’s maximum length can be adjusted which adjusts when the suspension is coupled. By increasing the maximum length it will increase the weight transfer. Reducing the maximum length reduces the weight transfer. The adjuster is threaded and can be turned in or out to allow more or less rod movement and weight transfer. The total range of the adjuster is 20mm with the standard position set in the middle. This means that there is 10mm on either side for more or less transfer depending on what an individual likes. An adjuster wrench is provided in the tool kit with measuring marks and indicators for standard, minimum and maximum settings. Before adjusting the control rod, clean the threads and use a spray lube before moving the locknut and adjuster.
The last component that can be adjusted is the front limiter strap. This strap is located on the front rail and affects the amount of front rail upward travel. The limiter strap has five mounting holes. The standard position is the second hole from the top. That means one longer position is available to put less weight on the skis, offering more weight transfer. The three shorter settings would increase the weight on the skis and offer less weight transfer. The limiter strap determines the position of the front rail and front arm travel. It also affects ride comfort, handling and weight transfer. This is a very sensitive adjustment, so we recommend the limiter strap be left in the stock position for most conditions; however, it is useful for racing or straight running applications and deep snow applications.
Yamaha does offer additional front and rear suspension springs for even more range. Ask your Yamaha dealer which spring would best suit your rider weight and needs.
This concludes this lesson in Suspension Tuning 101 on the all-new Yamaha Mon-Shock RA suspension. Our next lesson will be on the new Yamaha ProComfort Suspension, so check back only on Maximum Sled for Suspension Tuning 101.